The present invention relates to a device for interconnecting and disconnecting two individual optical fibers, and to a spreader-connector for optical fibers.
The spreader-connector of the present invention is a novel device enabling optical fibers that are grouped together in a ribbon or in a microsheath to be connected individually to individual optical fibers, and to do so in very little space.
Spreaders are known which enable the optical fibers of an optical fiber cable such as a ribbon or a microsheath to be separated.
They constitute guide devices of the type comprising a bundle of diverging channels, with the optical fibers penetrating into the device while grouped together in the cable, each fiber being received in a respective channel, and then the fibers leaving the spreader separated from one another.
Individual optical fiber connectors are also known comprising two connector elements for mounting at the ends of respective individual optical fibers that are to be connected together.
Such individual connectors are quite bulky in comparison with the optical fibers they connect together.
The present invention seeks to provide an individual connector that is compact and to combine these two functions of spreading and of individual connection in a single device of minimum size.
In a first aspect, the present invention provides a device for interconnecting and disconnecting two individual optical fibers, the device comprising:
two ferrules each having a front face and each being suitable for mounting at the end of a respective one of the optical fibers;
a connection channel in which the two ferrules can be engaged to face each other;
two axial retention means, each serving to limit axial displacements of a ferrule relative to the connection channel in a direction opposite to the direction for engaging it in said channel; and
a resilient member urging one of the ferrules to press the front faces of the two ferrules against each other while they are interconnected;
wherein for disconnection purposes the device includes an unlocking key suitable for disengaging the axial retention means of one of the ferrules, and wherein the resilient member is arranged so that when the unlocking key has disengaged the retention means, it pushes back said ferrule towards the outside of the alignment sleeve and gives rise to disconnection.
In other words, the individual connector of the invention is original in that it does not have means for assembling together and separating two connector elements acting one on the other, unlike conventional connectors in which each connector element includes firstly a ferrule retention means that is permanently operational, and secondly a separate means for assembly with the other connector which comes into operation only for connection purposes.
The invention thus consists in using the ferrule retention means as means for assembling together and separating optical fibers, thereby eliminating any separate assembly means.
The present invention also provides a device for individually connecting and disconnecting optical fibers grouped together in an optical fiber cable such as a ribbon or a microsheath with individual optical fibers, the device comprising:
a box comprising:
an insertion orifice for insertion of an optical fiber cable;
at its end opposite from said insertion orifice, a plurality of connection channels opening to the outside of the box; and
interposed between the insertion orifice and the connection channels, a spreading space enabling the fibers grouped together in the cable to spread apart from one another;
the device further comprising:
a plurality of internal ferrules each having a front face and each being suitable for being mounted on the end of a respective optical fiber spread out from the cable and for being engaged in a respective connection channel of the box from its end adjacent to the spreading space;
a plurality of external ferrules each having a front face and each being suitable for mounting on the end of a respective individual optical fiber and for being engaged in a respective connection channel from the outside of the box so as to face an internal ferrule;
in each connection channel, two axial retention means, each serving to limit axial displacements of a respective ferrule relative to the connection channel in a direction opposite from its engagement direction in said channel;
an unlocking key external to the box and suitable for disengaging the axial retention means of a single external ferrule in order to disconnect an individual optical fiber; and
in each connection channel, a resilient member urging one of the ferrules in its direction for engagement into the connection channel so as to press the front faces of the two ferrules against each other while they are interconnected, said resilient member also being arranged so that when the unlocking key disengages the axial retention means of an external ferrule, it pushes said external ferrule back towards the outside of the box and gives rise to individual disconnection of the two optical fibers.
It will be understood that the device of the invention makes it possible firstly to spread the optical fibers of a ribbon or microsheath type optical fiber cable, and secondly to connect each of the spread fibers from the cable individually to a respective individual fiber.
In this device, each connection channel forms an individual connector for an optical fiber.
This device of the invention is of reduced size because each of its connection channels is fitted only with means for retaining an external ferrule, unlocking being provided by the resilient member in each connection channel and by the unlocking key external to the box, which key is used individually to release each ferrule.
Thus, by eliminating the unlocking means in each connection channel, the size of each individual connector is reduced and it is possible to arrange a plurality of such individual connectors close together within the box.
In a particular embodiment, the retention means is constituted by a shoulder and by a clip having resilient fingers that move radially.
In a variant of this embodiment, the clip is part of the connection channel and the shoulder is part of the ferrule.
In a preferred embodiment, the ferrule presents a clearance portion adjacent to its shoulder, the cross-section of the clearance portion being smaller than that of the axial passage so as to leave radial clearance between the ferrule and said passage when the ferrule is inserted in the orifice.
In a preferred embodiment of the invention, the unlocking key has an end portion in the form of a longitudinally split hollow cylinder whose cross-section lies within the radial clearance that exists between the external ferrule and the channel and which can slide axially along the external ferrule between the ferrule and the wall of the axial passage in the body so as to come and spread apart the resilient fingers of the clip, thereby releasing the external ferrule.
In a particular embodiment, between its clearance portion and its opposite end remote from the front face, the ferrule includes a radially narrow portion which is terminated towards said opposite end by an axial abutment, and the unlocking key comprises, behind its end portion in the form of a split hollow cylinder, a projection which is free from any constraint when it overlies the radially narrow portion of the ferrule, thereby enabling the unlocking key to move axially relative to the ferrule, and which is suitable for going past the axial abutment by deforming elastically under the action of axial thrust exerted by an operator.
In an advantageous variant, the radially narrow portion of the ferrule is long enough to enable the unlocking key to be outside the connection channel when projection goes past the axial abutment of the external ferrule, said external ferrule being engaged in said channel and being retained by the clip.
Thus, the projection goes past the axial abutment to snap-fasten the unlocking key on the ferule outside the connection channel, thereby enabling the key to deform elastically.
By way of example, each ferrule can be obtained by being overmolded on the end of its individual optical fiber.
Preferably, the resilient member is a coil spring which acts solely on the internal ferrules.
In a particular embodiment, the device includes an alignment sleeve in each connection channel, the sleeve being suitable for receiving the facing front faces of an internal ferrule and of an external ferrule and for putting them into alignment.
The device of the invention is very small in size. For example, it can be made using ferrules having a diameter of 1.25 mm with adjacent connection channels at 3 mm intervals.